1. Field of the Invention
The invention relates to a method for producing semiconductor wafers composed of silicon having a diameter of at least 450 mm and having defect properties which make such semiconductor wafers suitable for use as substrates for the production of electronic components. The invention also relates to a semiconductor wafer composed of silicon having a diameter of 450 mm.
2. Background Art
Semiconductor wafers composed of silicon having a nominal diameter of 450 mm are currently being developed as substrates for the next generation. The developers are faced with a great challenge since the jump in diameter from 300 mm to 450 mm requires far more than simple adaptation and optimization of known production methods. One particular challenge consists of achieving the quality preferred at diameters of 300 mm, in particular with regard to defect properties. There is interest in defect properties in particular for defects brought about by accumulations of lattice vacancies to (“v-defects” hereinafter), or by accumulation of interstitial silicon, (“i-defects” hereinafter), and with regard to defects such as BMD (“bulk micro defects”) and OSF (“oxidation induced stacking faults”), in the formation of which oxygen precipitation plays an important part.
WO 2009/104534 A1 is representative of prior art showing that the jump in diameter from 300 mm to 450 mm has already been accomplished.
The report by Shiraishi et al., JOURNAL OF CRYSTAL GROWTH 229 (2001) 17-21, summarizes experience gained in the course of the development of a method for producing single crystals composed of silicon having a diameter of 400 mm. This experience includes the fact that it was not possible to produce semiconductor wafers which were free of defects or which exhibited a defect profile that is uniform over The diameter.